As millions of people prepared to meet their fiery Mayan deaths on Friday, one man remained cool and calm. According to Vladimir Putin, Russia's president - and now apparently chief prophecy maker - the world still has 4.5 billion years to go.

"I know when the end of the world will come," Putin said with his usual confidence during a press conference yesterday. "When?" asked a nervous journalist. "In about 4.5 billion years," he replied. Sighs of relief were breathed across Russia.

Yet the prophecy may have come too late. Around the world, people were flocking to sites touted as apocalypse-proof in hopes of avoiding the end of the world supposedly predicted by the Mayans thousands of years ago. In anticipation of an end-of-the-world influx, French gendarmes were dispatched to the village of Bugarach at the foot of the French Pyrenees, rumoured to be home to a giant UFO ready to whisk people to safety.

Mount Rtanj in Serbia boasted of its apocalypse survival properties, as did the Turkish village of Sirince. Authorities in China took a decidedly less jolly stance, arresting more than 500 people for allegedly spreading rumours about the world's impending demise.

Speaking on the eve of the alleged apocalypse, Putin urged a scientific approach. Calculating the sun's lifecycle at 7bn years, he said the star had already lived through 4.5bn years, leaving 4.5bn left. "That will be the end of the world," he surmised. Never mind that 4.5 plus 4.5 equals nine.

The exchange was one of many surreal moments inflicted upon a nation during Putin's annual marathon press conference yesterday, his first since returning to the presidency in May.

Putin was asked to comment on rumours that he had given a Russian passport to the actor Gerard Depardieu, fleeing high taxes in France. He replied with a monologue on the good nature of relations between Russia and France, despite the latter's membership of Nato. He then noted that artists tend to be sensitive, before adding: "If Gerard really wants to have residency in Russia, or a Russian passport, then we consider the question settled."

A journalist from the eastern city of Magadan inquired about Putin's health as the 60-year-old leader reportedly recovers from back trouble - a rare sign of age in a man who has worked hard to present an ever youthful and macho image. "You look like such an energetic and beautiful man," the journalist said.

Putin smiled and accused his political opponents of stirring rumours about his ill health. "On the question of my health I can answer in the traditional way: don't hold your breath."

Indeed, Putin held court like a man half his age, answering dozens of questions over four and a half hours in a room at a central Moscow conference centre packed with more than 1,000 journalists. He signed a birthday card for the daughter of a journalist from the Buddhist republic of Kalmykia and answered a rare question about his own children: "Everything is fine with my daughters. They're in Moscow. They study, work a bit. Everything is good in their personal lives and in terms of their professional growth. I am proud of them."

Yet unlike in years past, Putin also faced criticism. He was repeatedly questioned about a controversial new law that will ban Americans from adopting Russian children - a response to a recently adopted US law imposing visa bans and financial restrictions on Russian officials implicated in the death of the lawyer Sergei Magnitsky.

Putin said he supported the adoption ban and accused the US of adopting an anti-Russian law. "It's not really about officials," he said. "They're trying to remain in the past." Challenged over the adoption ban by a journalist who told his own story of being a foster father, Putin accused him of being a "sadomasochist" for taking the American side.

Putin also brushed off a question about the jailed oligarch Mikhail Khodorkovsky, whose sentence was reduced by two years yesterday, saying he had taken no part in imprisoning the man who had been Russia's richest man and was once seen as a potential political challenger.

Yet there were always journalists ready to ease the mood. As Putin neared the end of his marathon, a reporter from the southern city of Astrakhan said: "Enough Khodorkovsky, enough Magnitsky. I'm inviting you to go ice fishing!" Putin did not comment on whether he would accept the proposal. Another recommended naming one of the disputed Kuril islands, to which Japan also lays claim, after the powerful president. "Then it will become clear to everyone that this territory is Russian," the reporter said. Putin, ever bashful, recommended naming the island after a Russian writer instead.